This proposed Scientist Development Award for Clinicians (K2O) is an integrated 5 year development program including didactic study, research mentoring and research studies in the area of the neuroscience and genetics of Tourette Syndrome (TS). In a clinically ascertained sample of 53 TS probands and their 156 first degree relatives the candidate will use the fly study method, segregation analysis, and genetic modeling to identify the phenotypic features of TS which cosegregate with motor and phonic tics. It is hypothesized that TS, like other disorders of the basal ganglia, is characterized by abnormal movements, cognitive disfunction and a variety of psychiatric disorders including obsessive compulsive disorder (OCD), major depressive disorder (MDD), anxiety disorders (AD) and attention-deficit hyperactivity disorder (ADHD). The prevalence study will use a sample of 1500 school age children enrolled in an epidemiologic prevention program in the Baltimore Public Schools. Thirty children (2% of the sample) have been identified with symptoms consistent with TS in the first stage assessment. The second and third stage assessments will confirm these diagnoses, identify co-morbid conditions and modifiers of symptomatology. The hypotheses that will be tested are that tics and TS are frequently occurring problems in school- age children (tics= 1/10 and TS= 1/100) and occur with equal prevalence in African-American children and Caucasian children in this sample. It is also hypothesized that community ascertained subjects with TS will be at increased risk for the development of the profile of comorbid disorders seen in the subjects ascertained in the clinic including OCD, MDD, AD and ADHD. The identification of the phenotype and prevalence of TS is the essential next step in the search for the genetic etiology of TS and related disorders. The completion of the proposed didactic and research program will prepare the candidate to fully participate in the next generation of studies aimed at elucidating the etiology and pathogenesis of TS and related disorders in children and adolescence.